CN114243835A - Pre-charging circuit fault diagnosis circuit, method and device - Google Patents

Pre-charging circuit fault diagnosis circuit, method and device Download PDF

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Publication number
CN114243835A
CN114243835A CN202111554737.4A CN202111554737A CN114243835A CN 114243835 A CN114243835 A CN 114243835A CN 202111554737 A CN202111554737 A CN 202111554737A CN 114243835 A CN114243835 A CN 114243835A
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China
Prior art keywords
charging
battery
circuit
resistor
voltage
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Pending
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CN202111554737.4A
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Chinese (zh)
Inventor
王长治
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Evergrande New Energy Automobile Investment Holding Group Co Ltd
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Evergrande New Energy Automobile Investment Holding Group Co Ltd
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Publication of CN114243835A publication Critical patent/CN114243835A/en
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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
    • H02J7/007—Regulation of charging or discharging current or voltage
    • H02J7/00712—Regulation of charging or discharging current or voltage the cycle being controlled or terminated in response to electric parameters
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
    • B60L58/00—Methods or circuit arrangements for monitoring or controlling batteries or fuel cells, specially adapted for electric vehicles
    • B60L58/10—Methods or circuit arrangements for monitoring or controlling batteries or fuel cells, specially adapted for electric vehicles for monitoring or controlling batteries
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
    • H02J7/0029—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries with safety or protection devices or circuits
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
    • H02J7/007—Regulation of charging or discharging current or voltage
    • H02J7/00712—Regulation of charging or discharging current or voltage the cycle being controlled or terminated in response to electric parameters
    • H02J7/00714—Regulation of charging or discharging current or voltage the cycle being controlled or terminated in response to electric parameters in response to battery charging or discharging current
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
    • H02J7/007—Regulation of charging or discharging current or voltage
    • H02J7/00712—Regulation of charging or discharging current or voltage the cycle being controlled or terminated in response to electric parameters
    • H02J7/007182—Regulation of charging or discharging current or voltage the cycle being controlled or terminated in response to electric parameters in response to battery voltage
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T10/00—Road transport of goods or passengers
    • Y02T10/60—Other road transportation technologies with climate change mitigation effect
    • Y02T10/70—Energy storage systems for electromobility, e.g. batteries

Abstract

The application discloses precharge circuit fault diagnosis circuit, method and device, including: the system comprises a battery, a pre-charging loop resistor, charging equipment and a diagnosis unit, wherein the positive end of the battery is connected with the first end of the pre-charging loop resistor, and the negative end of the battery is connected with the negative end of the charging equipment; the second end of the pre-charging loop resistor is connected with the positive electrode end of the charging equipment; the diagnosis unit is respectively connected with the positive terminal and the negative terminal of the charging equipment and the positive terminal and the negative terminal of the battery, and is used for monitoring the resistance value or the current of the pre-charging loop resistor in the charging process of the charging equipment to the battery through the pre-charging loop resistor so as to diagnose the fault of the pre-charging loop corresponding to the pre-charging loop resistor. According to the embodiment of the application, the fault diagnosis of the high-voltage battery pre-charging loop can be performed in a vehicle charging scene, so that the coverage of the fault diagnosis is higher, and the safety of a vehicle is obviously improved.

Description

Pre-charging circuit fault diagnosis circuit, method and device
Technical Field
The present disclosure relates to the field of battery technologies, and in particular, to a circuit, a method, and an apparatus for diagnosing a fault in a pre-charge circuit.
Background
The electric automobile supplies power to loads such as a motor and the like through a power battery, so that the running of the automobile is realized. Because the loads on vehicles such as the motor and the like all comprise certain capacitive characteristic loads, if the battery directly connects high-voltage power supply to the vehicle loads, the capacitive characteristic that the load blocks direct current and alternating current can form extremely large current which is close to short circuit instantly. In order to avoid the damage of the components of the high-voltage loop caused by huge impact current, before the systems such as a motor of an electric automobile and the like are electrified to run, the high-voltage pre-charging loop of the battery needs to be started to pre-charge capacitive loads on the automobile.
Fig. 1 is a schematic circuit structure diagram of a vehicle pre-charging circuit, wherein K1 is a switch of the pre-charging circuit for controlling the on/off of the pre-charging circuit; rp is a pre-charging resistor of the pre-charging circuit, and is used for limiting the size of the pre-charging current flowing through the pre-charging circuit; k2 is a main switch for controlling the on-off of a main loop of the battery 10 for charging the load Z with large current; z is an electrical load on a high voltage circuit such as a motor on the vehicle, and the object of the precharge process is a capacitive load in the load Z. During pre-charging, the switch K2 remains open, the switch K1 is closed, and a pre-charging current is formed from the positive terminal of the battery 10 through the pre-charging circuit of the switch K1 and the pre-charging resistor Rp, and then enters the load Z, so that the capacitor in the load Z is charged through the pre-charging resistor Rp. The pre-charging of the capacitor ends when the voltage at the terminal Z of the load approaches the voltage at the terminal 10 of the battery.
The fault diagnosis of the pre-charging circuit is carried out simultaneously in the vehicle pre-charging process by the scheme, and is generally realized by detecting loop current, temperature or pre-charging voltage at a load end. Since the pre-charge circuit is also functionally a protection for the high-voltage circuit, damage to high-voltage components on the vehicle, such as high-voltage fuses or other electrical components, may have been caused simultaneously when a malfunction of the pre-charge circuit is detected.
Disclosure of Invention
The embodiment of the application aims to provide a pre-charging loop fault diagnosis circuit, a method and a device, which are used for solving the problem of low vehicle safety caused by the existing diagnosis mode.
In order to solve the above technical problem, the present specification is implemented as follows:
in a first aspect, a pre-charge circuit fault diagnosis circuit is provided, including: the system comprises a battery, a pre-charging loop resistor, charging equipment and a diagnosis unit, wherein the positive end of the battery is connected with the first end of the pre-charging loop resistor, and the negative end of the battery is connected with the negative end of the charging equipment; the second end of the pre-charging loop resistor is connected with the positive electrode end of the charging equipment; the diagnosis unit is respectively connected with the positive terminal and the negative terminal of the charging equipment and the positive terminal and the negative terminal of the battery, and is used for monitoring the resistance value or the current of the pre-charging loop resistor in the charging process of the charging equipment to the battery through the pre-charging loop resistor so as to diagnose the fault of the pre-charging loop corresponding to the pre-charging loop resistor.
Optionally, the circuit further includes a first switch and a second switch, the first switch is connected between the positive terminal of the battery and the first terminal of the pre-charging loop resistor, and the second switch is connected between the positive terminal of the battery and the positive terminal of the charging device;
and the diagnosis unit is also connected to the control end of the first switch and the control end of the second switch, and controls the first switch and the second switch to be switched on or switched off so as to form a first charging loop for charging the battery by the charging equipment through the pre-charging loop resistor or a second charging loop for directly charging the battery by the charging equipment.
In a second aspect, a precharge circuit fault diagnosis method is provided, which is applied to the precharge circuit fault diagnosis circuit of the first aspect, and includes: during the process that the charging equipment charges the battery through the pre-charging loop resistor, the diagnosis unit monitors the charging current output by the charging equipment, the voltage of the battery and the voltage output by the charging equipment; the diagnosis unit diagnoses a fault of the pre-charge circuit based on the charging current, the voltage of the battery, the voltage output from the charging device, and a preset resistance value of the pre-charge circuit resistor.
Optionally, the diagnosing unit diagnoses the fault of the pre-charge circuit according to the charging current, the voltage of the battery, the voltage output by the charging device, and a preset resistance value of the pre-charge circuit resistor, and includes:
calculating the current actual resistance value of the pre-charging loop resistor according to the currently detected charging current, the voltage of the battery and the voltage output by the charging equipment;
calculating a first error value between the actual resistance value and the preset resistance value;
and if the first error value exceeds a first preset error range, diagnosing that the pre-charging circuit has a fault.
Optionally, the diagnosing unit diagnoses the fault of the pre-charge circuit according to the charging current, the voltage of the battery, the voltage output by the charging device, and a preset resistance value of the pre-charge circuit resistor, and includes:
calculating a theoretical current value corresponding to the pre-charging loop resistor according to the currently detected voltage of the battery, the voltage output by the charging equipment and the preset resistance value of the pre-charging loop resistor;
calculating a second error value between the currently detected charging current and the theoretical current value;
and if the second error value exceeds a second preset error range, diagnosing that the pre-charging circuit has a fault.
Optionally, if the precharge circuit is diagnosed to have a fault, the method further includes:
and controlling the charging equipment to stop charging the battery through the diagnosis unit, and sending corresponding fault data.
Optionally, before the charging device charges the battery through the pre-charge loop resistor, the method further includes:
under the condition that a charging demand for charging the battery is received, the diagnosis unit sets a charging mode of the charging equipment to be a constant voltage charging mode and sets a constant voltage value output by the charging equipment, wherein the constant voltage value is determined according to the voltage of the battery, a preset resistance value of a pre-charging loop resistor and a preset current value, and the preset current value is smaller than a current value output by the charging equipment according to the charging demand;
transmitting, by the diagnosis unit, a constant voltage charging mode and a constant voltage value output by the charging device to the charging device; wherein the content of the first and second substances,
according to the constant voltage value, the charging device charges the battery through the pre-charging loop resistor.
Optionally, before the charging device charges the battery through the pre-charge loop resistor, the method further includes:
under the condition that a charging demand for charging the battery is received, setting a charging mode of the charging equipment to be a constant current charging mode and setting a constant current value output by the charging equipment by the diagnosis unit, wherein the constant current value is smaller than a current value output by the charging equipment according to the charging demand;
sending a constant current charging mode and a constant current value output by the charging device to the charging device through the diagnosis unit; wherein the content of the first and second substances,
according to the constant current value, the charging device charges the battery through the pre-charging loop resistor.
Optionally, if it is diagnosed that there is no fault in the pre-charging circuit, the method further includes:
sending a charging demand to the charging device by the diagnostic unit;
and according to the current value corresponding to the charging requirement, the charging equipment directly charges the battery.
In a third aspect, a pre-charging circuit fault diagnosis device is provided, which includes a memory and a processor electrically connected to the memory, the memory storing a computer program executable by the processor, and the computer program implementing the method according to the second aspect when executed by the processor.
In the embodiment of the application, the pre-charging loop fault diagnosis circuit comprises a battery, a pre-charging loop resistor, a charging device and a diagnosis unit, wherein the positive end of the battery is connected with the first end of the pre-charging loop resistor, and the negative end of the battery is connected with the negative end of the charging device; the second end of the pre-charging loop resistor is connected with the positive electrode end of the charging equipment; the diagnosis unit is respectively connected with the positive terminal and the negative terminal of the charging equipment and the positive terminal and the negative terminal of the battery, and is used for monitoring the resistance value or the current of the pre-charging loop resistor in the process of charging the battery by the pre-charging loop resistor through the charging equipment so as to diagnose the fault of the pre-charging loop corresponding to the pre-charging loop resistor, thereby increasing the fault diagnosis of the high-voltage battery pre-charging loop under the vehicle charging scene on the basis of the existing electric vehicle charging technology, ensuring higher coverage of the fault diagnosis and obviously improving the vehicle safety.
According to the embodiment of the application, the direction of the charging current flowing through the pre-charging circuit cannot enter the high-voltage load of the vehicle, fault diagnosis can be carried out without switching on the motor load of the vehicle, and the damage to the power utilization component at the high-voltage load end of the vehicle, which is possibly caused by the fault of the pre-charging circuit, is avoided. And, can charge the beginning at the vehicle, can be so that electric vehicle pre-charge return circuit trouble can be found in advance to remind the user to maintain and handle as early as possible, avoid the user just to discover the time distress that the vehicle trouble leads to can't going when starting the vehicle trip, reduce the influence to the user trip after the trouble takes place, promote user experience.
Drawings
The accompanying drawings, which are included to provide a further understanding of the application and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the application and together with the description serve to explain the application and not to limit the application. In the drawings:
fig. 1 is a schematic circuit diagram of a precharge circuit of a vehicle.
Fig. 2 is a block diagram showing a structure of a precharge circuit fault diagnosis circuit according to an embodiment of the present application.
Fig. 3 is a circuit configuration example diagram of a precharge circuit fault diagnosis circuit according to an embodiment of the present application.
Fig. 4 is a flowchart illustrating a method for diagnosing a fault in a pre-charge circuit according to an embodiment of the present disclosure.
Fig. 5 is a block diagram showing the structure of a precharge circuit failure diagnosis apparatus according to an embodiment of the present application.
Detailed Description
The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are some, but not all, embodiments of the present application. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application. The reference numbers in the present application are only used for distinguishing the steps in the scheme and are not used for limiting the execution sequence of the steps, and the specific execution sequence is described in the specification.
In order to solve the problems in the prior art, an embodiment of the present application provides a fault diagnosis circuit for a pre-charge circuit, which includes a battery, a pre-charge circuit resistor, a charging device, and a diagnosis unit. The positive end of the battery is connected with the first end of the pre-charging loop resistor, and the negative end of the battery is connected with the negative end of the charging equipment; the second end of the pre-charging loop resistor is connected with the positive electrode end of the charging equipment; the diagnosis unit is respectively connected with the positive terminal and the negative terminal of the charging equipment and the positive terminal and the negative terminal of the battery, and is used for monitoring the resistance value or the current of the pre-charging loop resistor in the charging process of the charging equipment to the battery through the pre-charging loop resistor so as to diagnose the fault of the pre-charging loop corresponding to the pre-charging loop resistor.
Fig. 2 is a block diagram of a precharge circuit fault diagnosis circuit according to an embodiment of the present application, which schematically shows a connection relationship between components in the diagnosis circuit in a transmission direction of a current output from a charging device.
As shown in fig. 2, the pre-charge circuit fault diagnosis circuit 100 includes a battery 10, a pre-charge circuit resistor 20, a charging device 30, and a diagnosis unit 40. In the embodiment of the present application, the pre-charge circuit resistor 20 is disposed on a charge circuit in which the charging device 30 supplies a charging current to the battery 10 of the vehicle, and is connected to the battery 10 and the charging device 30, respectively.
The pre-charging circuit resistor 20 includes a pre-charging resistor Rp and a resistor connected to a wiring harness disposed on the pre-charging circuit, and the resistance of the wiring harness is usually very small, and is on the order of 0.1 ohm or 0.01 ohm, which can be ignored. For a specific vehicle, the resistance value of the corresponding pre-charging resistor Rp is a fixed theoretical design value, and the resistance value design of the pre-charging resistor may be different for different vehicles. In general, the pre-charging resistor of the small electric automobile has a resistance value of 50-60 ohms, and the pre-charging resistor of the large electric bus has a resistance value of 100-200 ohms.
The battery 10 and the pre-charging circuit resistor 20 correspondingly form a pre-charging circuit of the vehicle, and the diagnosis unit 40 is connected with the battery 10 and the charging device 30 respectively, so that whether the pre-charging circuit has a fault can be diagnosed by monitoring whether the resistance value or the current of the pre-charging circuit resistor 20 on the charging circuit is abnormal.
Optionally, the pre-charging loop fault diagnosis circuit further includes a first switch and a second switch, the first switch is connected between the positive terminal of the battery and the first terminal of the pre-charging loop resistor, and the second switch is connected between the positive terminal of the battery and the positive terminal of the charging device. And the diagnosis unit is also connected to the control end of the first switch and the control end of the second switch, and controls the first switch and the second switch to be switched on or switched off so as to form a first charging loop for charging the battery by the charging equipment through the pre-charging loop resistor or a second charging loop for directly charging the battery by the charging equipment.
A first charging loop of the charging equipment for charging the battery through the pre-charging loop resistor can be formed by controlling the first switch to be closed and the second switch to be opened; by controlling the first switch to be open and the second switch to be closed, or both the first switch and the second switch to be closed, a second charging loop can be formed in which the charging device directly charges the battery.
Next, an example of the precharge circuit fault diagnosis circuit of the embodiment of the present application is described with reference to fig. 3.
As shown in fig. 3, in this example, the charging device is a charging post 30, the pre-charge circuit resistance is a pre-charge resistance Rp, and the diagnostic unit includes a battery management system 42 and a current sensor 44. Along the current direction of charging stake 30 output, fill electric pile 30, pre-charge resistance Rp, switch K11, battery 10 and constitute first charging circuit, fill electric pile 30, switch K22, battery 10 and constitute the second charging circuit.
The battery management system 42 is connected to the positive and negative terminals of the battery 10 through voltage collection lines 422 and 424, respectively, for collecting the voltage value of the battery 10. Similarly, the battery management system 42 is connected to the positive and negative terminals of the charging pile 30 through voltage collecting lines 426 and 428, respectively, for collecting the voltage value output by the charging pile 30. The current sensor 44 is disposed on a charging loop close to the battery 10, and the battery management system 42 collects a current value of the charging loop corresponding to the charging process of the charging pile 30 to the battery 10 through the pre-charging resistor Rp through the current collecting line 442. The battery management system 42 may also send control signals to the switches K11, K22 to control the opening or closing of the switches K11, K22. The battery management system 42 may also establish a charging communication connection with the charging pile 30, and send a corresponding charging demand message to the charging pile 30 when receiving a charging demand of a vehicle. The charging communication between the battery management system 42 and the charging pile 30 may adopt an existing standard communication mode, for example, the transmitted battery charging demand message is a BCL message in the national standard.
Referring now to fig. 4, fig. 4 is a flowchart illustrating a method for diagnosing a fault in a pre-charge circuit according to an embodiment of the present disclosure, which is applied to the circuit for diagnosing a fault in a pre-charge circuit.
As shown in fig. 4, the method comprises the following steps:
102, in the process that the charging equipment charges the battery through the pre-charging loop resistor, monitoring the charging current output by the charging equipment, the voltage of the battery and the voltage output by the charging equipment by a diagnosis unit;
and 104, diagnosing the fault of the pre-charging loop by the diagnosis unit according to the charging current, the voltage of the battery, the voltage output by the charging equipment and the preset resistance value of the pre-charging loop resistor.
Next, a precharge circuit fault diagnosis method according to an embodiment of the present application will be described with reference to a circuit configuration diagram illustrated in fig. 3.
In step 102, the battery management system 42 collects the charging current output by the charging pile detected in real time by the current sensor 44 through the current collection line 442, collects the voltage of the battery 10 through the voltage collection lines 422 and 424, and collects the voltage output by the charging pile 30 through the voltage collection lines 426 and 428.
Based on the solution provided by the foregoing embodiment, optionally, in step 104, the diagnosing unit diagnoses the fault of the pre-charge circuit according to the charging current, the voltage of the battery, the voltage output by the charging device, and the preset resistance value of the pre-charge circuit resistor, and includes: calculating the current actual resistance value of the pre-charging loop resistor according to the currently detected charging current, the voltage of the battery and the voltage output by the charging equipment; calculating a first error value between the actual resistance value and the preset resistance value; and if the first error value exceeds a first preset error range, diagnosing that the pre-charging circuit has a fault.
In this embodiment, the actual resistance of the pre-charge circuit resistor is monitored to determine whether the pre-charge circuit has a fault.
Under the condition that the battery management system 42 detects the charging current I and simultaneously detects the voltage V2 output by the charging pile 30 and the voltage V1 at the end of the battery 10, the actual resistance Rp _ act of the pre-charging circuit is calculated by ohm's law, as represented by the following formula:
Rp_act＝(V2-V1)/I
whether the corresponding resistance value error falls within a design error range, such as 1% -2%, is judged by calculating a preset resistance value of the pre-charging loop resistor, namely a theoretical design value Rp _ dsgn, and a difference value (Rp _ act-Rp _ dsgn) of the measured actual resistance value Rp _ act. And if the resistance value error exceeds the design error range, namely the actual resistance value of the resistor of the pre-charging circuit is overlarge, diagnosing that the pre-charging circuit corresponding to the resistor of the pre-charging circuit has a fault. For example, there may be degradation of the wiring harness or damage to the pre-charge resistive element, etc.
Based on the solution provided by the foregoing embodiment, optionally, in step 104, the diagnosing unit diagnoses the fault of the pre-charge circuit according to the charging current, the voltage of the battery, the voltage output by the charging device, and the preset resistance value of the pre-charge circuit resistor, and includes: calculating a theoretical current value corresponding to the pre-charging loop resistor according to the currently detected voltage of the battery, the voltage output by the charging equipment and the preset resistance value of the pre-charging loop resistor; calculating a second error value between the currently detected charging current and the theoretical current value; and if the second error value exceeds a second preset error range, diagnosing that the pre-charging circuit has a fault.
In this embodiment, the current flowing through the resistor of the pre-charging circuit is monitored to determine whether the pre-charging circuit has a fault.
Under the condition that the battery management system 42 detects the charging current I and simultaneously detects the voltage V2 output by the charging pile 30 and the voltage V1 at the end of the battery 10, a theoretical current value I 'corresponding to the pre-charging loop resistor is calculated through a preset resistance Rp _ dsgn and ohm's law of the pre-charging loop resistor, as represented by the following formula:
I’＝(V2-V1)/Rp_dsgn
and judging whether the corresponding current value error falls within a design error range, such as 1-2%, by calculating the theoretical current value I 'of the resistor of the pre-charging loop and the difference value (I-I') of the actually measured charging current I. And if the current value error exceeds the design error range, namely the theoretical current value of the resistor of the pre-charging circuit is too small, diagnosing that the pre-charging circuit corresponding to the resistor of the pre-charging circuit has a fault. For example, there may be degradation of the wiring harness or damage to the pre-charge resistive element, etc.
Optionally, in an embodiment, if the precharge circuit is diagnosed to have a fault, the method further includes: and controlling the charging equipment to stop charging the battery through the diagnosis unit, and sending corresponding fault data.
In an embodiment of monitoring the actual resistance of the pre-charge circuit resistor to determine whether the pre-charge circuit has a fault, the fault data may include the actual resistance and the preset resistance of the pre-charge circuit resistor. In embodiments where the pre-charge circuit is determined to be faulty by monitoring the current flowing through the pre-charge circuit resistor, the fault data may include the actual current value and the theoretical current value of the pre-charge circuit resistor.
The transmitted fault data can be provided for relevant personnel to check, so that the severity of the fault of the pre-charging circuit can be quickly known through the quantized fault data, and corresponding maintenance measures can be taken in time.
Optionally, in an embodiment, before the charging device charges the battery through the pre-charge circuit resistor in step 102, the method further includes: under the condition that a charging demand for charging the battery is received, the diagnosis unit sets a charging mode of the charging equipment to be a constant voltage charging mode and sets a constant voltage value output by the charging equipment, wherein the constant voltage value is determined according to the voltage of the battery, a preset resistance value of a pre-charging loop resistor and a preset current value, and the preset current value is smaller than a current value output by the charging equipment according to the charging demand; transmitting, by the diagnosis unit, a constant voltage charging mode and a constant voltage value output by the charging device to the charging device; wherein the charging device charges the battery through the pre-charge loop resistor according to the constant voltage value.
Optionally, in another embodiment, before the charging device charges the battery through the pre-charge circuit resistor in step 102, the method further includes: under the condition that a charging demand for charging the battery is received, setting a charging mode of the charging equipment to be a constant current charging mode and setting a constant current value output by the charging equipment by the diagnosis unit, wherein the constant current value is smaller than a current value output by the charging equipment according to the charging demand; sending a constant current charging mode and a constant current value output by the charging device to the charging device through the diagnosis unit; wherein the charging device charges the battery via the pre-charge loop resistor according to the constant current value.
The diagnosis of the pre-charging loop is realized through the software and hardware control process of the vehicle battery management system in the process of charging the vehicle by using the charging equipment. Therefore, when the vehicle has a charging demand, for example, a charging gun is inserted into a corresponding charging post, a normal charging operation is started. And the charging pile and the vehicle battery management system carry out charging communication handshake and parameter configuration according to national standard requirements.
At this time, the battery management system 42 of fig. 3 closes the switch K11, keeps the switch K22 in an open state, and enters a charging phase corresponding to the first charging loop.
The battery management system 42 sends a battery charging demand message to the charging pile 30, and the battery charging demand message includes different corresponding parameters according to whether the charging mode is the constant voltage mode or the constant current mode, which are respectively described below.
When the charging mode is the constant voltage mode, the parameters included in the message include the constant voltage charging mode and the constant voltage value corresponding to the voltage requirement.
In the fault diagnosis stage of the pre-charging circuit, in order to prevent the pre-charging circuit from being damaged by overlarge charging current flowing through the resistor of the pre-charging circuit, a charging pile needs to be arranged to output a smaller charging current, such as 1-3A. Therefore, in the constant voltage mode, the formula for setting the constant voltage value is as follows:
Vreq＝Vpack+Rp_dsgn×I
wherein Vreq is a constant voltage value to be output by the charging pile 30, Vpack is a current voltage of the battery 10, Rp _ dsgn is a theoretical design value of the pre-charging resistance Rp, and I is a charging current value correspondingly output by the charging pile 30 when the battery 10 is charged according to the constant voltage value.
In addition, a protection limit value of the current demand can be set, so that the current output by the charging pile 30 during constant-voltage charging does not exceed the protection limit, for example, 2A-3A.
At this time, in the constant voltage charging mode, the battery management system 42 sends the parameters included in the battery charging request message to the charging pile 30, including the constant voltage charging mode, the constant voltage value, and the current protection limit value.
When the charging mode is the constant current mode, the parameters included in the message include the constant current charging mode and the constant current value corresponding to the current demand.
In the fault diagnosis stage of the pre-charging circuit, in order to prevent the damage to the pre-charging circuit caused by the overlarge charging current flowing through the resistor of the pre-charging circuit, a charging pile needs to be arranged to output a smaller constant charging current, such as 1-3A.
Thus, the charging pile 30 can start charging the battery 10 through the first charging loop via the pre-charging resistor Rp according to the charging parameters corresponding to the constant voltage mode or the constant current mode sent by the battery management system 42, so as to perform the following steps 102 and 104 to perform the fault diagnosis of the pre-charging loop.
According to the national standard of charging communication, the current request time interval from the battery management system 42 to the charging pile 30 is 250ms, so that the fault diagnosis time in the embodiment of the present application can reach the second level, and the fault diagnosis time of the pre-charging circuit can be set to 1-2 seconds in order to not delay normal charging.
In the embodiment of the present application, no matter in the constant voltage charging mode or the constant current charging mode, the direction of the charging current flowing through the pre-charging circuit in the embodiment of the present application does not enter the high voltage load of the vehicle, and the current is extremely small, so that even if a fault of the pre-charging circuit is diagnosed, secondary damage to relevant parts of the vehicle is extremely difficult to cause.
Optionally, in an embodiment, if it is diagnosed that there is no fault in the priming circuit, the method further includes: sending a charging demand to the charging device by the diagnostic unit; and according to the current value corresponding to the charging requirement, the charging equipment directly charges the battery.
When the diagnosis of the pre-charging circuit is completed and no fault exists in the diagnosis, the battery management system 42 controls the switch K22 to be closed and controls the switch K11 to be opened, and starts to send a charging demand message of the normal charging demand of the battery 10 to the charging pile 30 in real time, so that the charging pile 30 starts to charge normally.
In the embodiment of the application, the pre-charging loop fault diagnosis circuit comprises a battery, a pre-charging loop resistor, a charging device and a diagnosis unit, wherein the positive terminal of the battery is connected with the first end of the pre-charging loop resistor, and the negative terminal of the battery is connected with the negative terminal of the charging device; the second end of the pre-charging loop resistor is connected with the positive electrode end of the charging equipment; the diagnosis unit is respectively connected with the positive terminal and the negative terminal of the charging equipment and the positive terminal and the negative terminal of the battery, and monitors the resistance value or the current of the pre-charging loop resistor in the process of charging the battery by the pre-charging loop resistor of the charging equipment so as to diagnose the fault of the pre-charging loop corresponding to the pre-charging loop resistor, thereby increasing the fault diagnosis of the high-voltage battery pre-charging loop under the vehicle charging scene on the basis of the existing electric vehicle charging technology, ensuring the coverage of the fault diagnosis to be higher and obviously improving the vehicle safety.
According to the embodiment of the application, the direction of the charging current flowing through the pre-charging circuit cannot enter the high-voltage load of the vehicle, fault diagnosis can be carried out without switching on the motor load of the vehicle, and the damage to the power utilization component at the high-voltage load end of the vehicle, which is possibly caused by the fault of the pre-charging circuit, is avoided.
In addition, the current involved in the fault diagnosis of the pre-charging circuit is extremely small, and even if the fault of the pre-charging circuit is diagnosed, secondary damage to relevant parts of the vehicle is extremely difficult to cause.
The embodiment of the application starts at the vehicle charging, so that the fault of the electric vehicle pre-charging loop can be found in advance, the maintenance and the processing of a user can be reminded as soon as possible, the time distress that the user cannot travel due to the fact that the user finds the vehicle fault when the vehicle is started to travel is avoided, the influence on the user travel after the fault occurs is reduced, and the user experience is improved.
Optionally, an embodiment of the present application further provides a fault diagnosis device for a pre-charge circuit, and fig. 5 is a block diagram of a structure of the fault diagnosis device for the pre-charge circuit according to the embodiment of the present application.
As shown in fig. 5, the precharge circuit fault diagnosis apparatus 2000 includes a memory 2200 and a processor 2400 electrically connected to the memory 2200, where the memory 2200 stores a computer program that can be executed by the processor 2400, and the computer program, when executed by the processor, implements each process of any one of the above embodiments of the precharge circuit fault diagnosis method, and can achieve the same technical effect, and is not repeated here to avoid repetition.
The embodiment of the present application further provides a computer-readable storage medium, where a computer program is stored on the computer-readable storage medium, and when the computer program is executed by a processor, the computer program implements each process of any one of the above embodiments of the method for diagnosing a fault of a pre-charge circuit, and can achieve the same technical effect, and is not described herein again to avoid repetition. The computer-readable storage medium may be a Read-Only Memory (ROM), a Random Access Memory (RAM), a magnetic disk or an optical disk.
It should be noted that, in this document, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other like elements in a process, method, article, or apparatus that comprises the element.
Through the above description of the embodiments, those skilled in the art will clearly understand that the method of the above embodiments can be implemented by software plus a necessary general hardware platform, and certainly can also be implemented by hardware, but in many cases, the former is a better implementation manner. Based on such understanding, the technical solutions of the present application may be embodied in the form of a software product, which is stored in a storage medium (such as ROM/RAM, magnetic disk, optical disk) and includes instructions for enabling a terminal (such as a mobile phone, a computer, a server, an air conditioner, or a network device) to execute the method according to the embodiments of the present application.
While the present embodiments have been described with reference to the accompanying drawings, it is to be understood that the invention is not limited to the precise embodiments described above, which are meant to be illustrative and not restrictive, and that various changes may be made therein by those skilled in the art without departing from the spirit and scope of the invention as defined by the appended claims.

Claims (10)

1. The pre-charging loop fault diagnosis circuit is characterized by comprising a battery, a pre-charging loop resistor, a charging device and a diagnosis unit,
the positive end of the battery is connected with the first end of the pre-charging loop resistor, and the negative end of the battery is connected with the negative end of the charging equipment;
the second end of the pre-charging loop resistor is connected with the positive end of the charging equipment;
the diagnosis unit is respectively connected with the positive terminal and the negative terminal of the charging equipment and the positive terminal and the negative terminal of the battery, and is used for monitoring the resistance value or the current of the pre-charging loop resistor in the charging process of the charging equipment to the battery through the pre-charging loop resistor so as to diagnose the fault of the pre-charging loop corresponding to the pre-charging loop resistor.
2. The circuit of claim 1, further comprising a first switch connected between the positive terminal of the battery and the first terminal of the pre-charge loop resistor, and a second switch connected between the positive terminal of the battery and the positive terminal of the charging device;
the diagnosis unit is further connected to the control end of the first switch and the control end of the second switch, and controls the first switch and the second switch to be closed or opened, so as to form a first charging loop for the charging device to charge the battery through the pre-charging loop resistor, or a second charging loop for the charging device to directly charge the battery.
3. A precharge circuit fault diagnosis method applied to the precharge circuit fault diagnosis circuit according to claim 1 or 2, characterized by comprising:
the diagnosis unit monitors a charging current output by the charging device, a voltage of the battery and a voltage output by the charging device during charging of the battery by the charging device via the pre-charging loop resistor;
and the diagnosis unit diagnoses the fault of the pre-charging loop according to the charging current, the voltage of the battery, the voltage output by the charging equipment and the preset resistance value of the pre-charging loop resistor.
4. The method of claim 3, wherein the diagnosing unit diagnoses the fault in the pre-charge circuit based on the charging current, the voltage of the battery, the voltage output by the charging device, and the pre-set resistance of the pre-charge circuit resistor, including:
calculating the current actual resistance value of the pre-charging loop resistor according to the currently detected charging current, the voltage of the battery and the voltage output by the charging equipment;
calculating a first error value between the actual resistance value and the preset resistance value;
and if the first error value exceeds a first preset error range, diagnosing that the pre-charging circuit has a fault.
5. The method of claim 3, wherein the diagnosing unit diagnoses the fault in the pre-charge circuit based on the charging current, the voltage of the battery, the voltage output by the charging device, and the pre-set resistance of the pre-charge circuit resistor, including:
calculating a theoretical current value corresponding to the pre-charging loop resistor according to the currently detected voltage of the battery, the voltage output by the charging equipment and the preset resistance value of the pre-charging loop resistor;
calculating a second error value between the currently detected charging current and the theoretical current value;
and if the second error value exceeds a second preset error range, diagnosing that the pre-charging circuit has a fault.
6. The method of claim 4 or 5, wherein if the pre-charge circuit is diagnosed as malfunctioning, further comprising:
and controlling the charging equipment to stop charging the battery through the diagnosis unit, and sending corresponding fault data.
7. The method of claim 3, further comprising, prior to the charging device charging the battery via the pre-charge loop resistance:
under the condition that a charging demand for charging the battery is received, the diagnosis unit sets a charging mode of the charging equipment to be a constant voltage charging mode and sets a constant voltage value output by the charging equipment, wherein the constant voltage value is determined according to the voltage of the battery, a preset resistance value of the pre-charging loop resistor and a preset current value, and the preset current value is smaller than a current value output by the charging equipment according to the charging demand;
transmitting, by the diagnostic unit, the constant voltage charging mode and a constant voltage value output by the charging device to the charging device; wherein the content of the first and second substances,
according to the constant voltage value, the charging device charges the battery through the pre-charging loop resistor.
8. The method of claim 3, further comprising, prior to the charging device charging the battery via the pre-charge loop resistance:
under the condition that a charging demand for charging the battery is received, the diagnosis unit sets a charging mode of the charging equipment to be a constant current charging mode and sets a constant current value output by the charging equipment, wherein the constant current value is smaller than a current value output by the charging equipment according to the charging demand;
sending the constant current charging mode and the constant current value output by the charging device to the charging device through the diagnosis unit; wherein the content of the first and second substances,
according to the constant current value, the charging device charges the battery through the pre-charging loop resistor.
9. The method of claim 7 or 8, wherein if the pre-charge circuit is diagnosed as not having a fault, further comprising:
transmitting, by the diagnostic unit, the charging demand to the charging device;
and according to the current value corresponding to the charging requirement, the charging equipment directly charges the battery.
10. A precharge circuit fault diagnosis apparatus characterized by comprising: a memory and a processor electrically connected to the memory, the memory storing a computer program executable on the processor, the computer program when executed by the processor implementing the method of any one of claims 3 to 9.
CN202111554737.4A 2021-10-09 2021-12-17 Pre-charging circuit fault diagnosis circuit, method and device Pending CN114243835A (en)

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CN112462228A (en) * 2020-11-11 2021-03-09 浙江飞碟汽车制造有限公司 Electric vehicle quick charge loop diagnosis system and diagnosis method thereof

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CN104104137A (en) * 2014-07-23 2014-10-15 山东大学 Lithium iron phosphate power battery management system and management method
US20180238935A1 (en) * 2017-02-23 2018-08-23 Denso Corporation Abnormality diagnosis apparatus
CN209419260U (en) * 2019-01-15 2019-09-20 北汽福田汽车股份有限公司 A kind of charging circuit, power battery, charging system and vehicle
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